单选题During the Second World War, all important resources in the U. S. were Uallocated/U by the federal government.

单选题We had to turn to dried milk as fresh milk wasn"t available.

单选题The company takes environmental issues into account wherever possible.

单选题Screen Test Every year millions of women are screened with X-rays to pick up signs of breast cancer. If this happens early enough, the disease can often be treated 1 . According to a survey published last year, 21 countries have screening programmes. Nine of them, including Australia, Canada, the U.S. and Spain, 2 women under 50. But the medical benefits of screening these younger 3 are controversial, partly because the radiation brings a small risk of inducing cancer. 4 , younger women must be given higher doses of X-rays because their breast tissue is denser. Researchers at the Polytechnic University of Valencia analyzed the effect 5 screening more than 160,000 women at 11 local clinics. After estimating the women"s cumulative dose of radiation, they used two models to calculate the number of extra cancers this 6 cause. The mathematical model recommended by Britain"s National Radiological Protection Board (NRPB) predicted that the screening programme would 7 36 cancers per 100,000 women, 18 of them fatal. The model preferred by the UN Scientific Committee on the Effects of Atomic Radiation 8 a lower figure of 20 cancers. The researchers argue that the level of radiation-induced cancers is "not very significant" 9 to the far larger number of cancers that are discovered and treated. The Valencia programme, they say, detects between 300 and 450 10 of breast cancer in every 100,000 women screened. But they 11 that the risk of women contracting cancer from radiation could be reduced by between 40 and 80 percent if screening began at 50 instead of 45, because they would be exposed to 12 radiation. The results of their study, they suggest, could help "optimise the technique" for breast cancer screening. " 13 is a trade-off between the diagnostic benefits of breast screening and its risks," admits Michael Clark of the NRPB. But he warns that the study should be interpreted with caution. "On the 14 of the current data, for every 10 cancers successfully detected and prevented there is a risk of 15 one later in life. That"s why radiation exposure should be minimised in any screening programme."

单选题The experimenters thought Washoe was intelligent__________

单选题We reckoned there was only one man who is fit for the post.

单选题{{B}}第二篇{{/B}} {{B}} Ancient Egypt Brought Down by Famine{{/B}} Even ancient Egypt's mighty pyramid (金字塔) builders were powerless in the face of the famine (饥荒) that helped bring down their civilization around 2180 BC. Now evidence collected from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blame—and the same or worse could happen today. The ancient Egyptians depended on the Nile's annual floods to irrigate their crops. But any change in climate that pushed the African monsoons (季风) southwards out of Ethiopia would have reduced these floods. Declining rains in the Ethiopian highlands would have meant fewer plants to stabilize the soil. When rain did fall it would have washed large amounts of soil into the Blue Nile and into Egypt, along with sediment (沉积) from the White Nile. Blue Nile mud has a different isotope (同位素) signature from that of the White Nile. So by analyzing isotope differences in mud deposited in the Nile Delta, Michael Krom of Leeds University worked out what proportion of sediment came from each branch of the river. Krem reasons that during periods of drought, the amount of Blue Nile mud in the river would be relatively high. He found that one of these periods, from 4500 to 4200 years ago, immediately came before the fall of the Egypt's Old Kingdom. The weakened waters would have been disaster for the Egyptians. "Changes that affect food supply don't have to be very large to have a ripple (波浪) effect in societies," says Bill Ryan of the Lamont Doherty Earth Observatory in New York. Similar 'events today could be even more devastating, says team member Daniel Stanley, a scientist from the Smithsonian Institution in Washington DC. "Anything humans do to shift the climate belts would have an even worse effect along the Nile system today because the populations have increased dramatically."

单选题Hundreds of buildings were Uwrecked/U by the earthquake

单选题These are our motives for doing it.

单选题The Smog (烟雾) For over a month, Indonesia was in crisis. Forest fires raged out of control as the country suffered its worst drought for 50 years. Smoke from the fires mixed with sunlight and hot dry air to form a cloud of smog. This pollution quickly spread and within days it was hanging over neighboring countries including Malaysia, Singapore and Thailand. When the smoke combined with pollution from factories and cars, it soon became poisonous (有毒的). Dangerous amounts of CO became trapped under the smog and pollution levels rose. People wheezed (喘息) and coughed as they left the house and their eyes watered immediately. The smog made it impossible to see across streets and whole cities disappeared as grey soot (烟灰) covered everything. In some areas, water was hosed (用胶管浇) from high-rise city buildings to try and break up the smog. Finally, heavy rains, which came in November, put out the fires and clear the air. But the environmental costs and health problems will remain. Many people from South-Eastern Asian cities already suffer from breathing huge amounts of car exhaust fumes (汽车排放的废气) and factory pollution. Breathing problems could well increase and many non-sufferers may have difficulties for the first time. Wildlife has suffered too. In lowland forests, elephants, deer, and tigers have been driven out of their homes by smog. But smog is not just an Asian problem. In fact, the word was first used in London in 1905 to describe the mixture of smoke and thick fog. Fog often hung over the capital. Sometimes the smog was so thick and poisonous that people were killed by breathing problems or in accidents. About 4,000 Londoners died within five days as a result of thick smog in 1952.

单选题The author of the passage could not go to sleep partly because

单选题Most animal fats are saturated, containing more hydrogen than carbon, and do not spoil as easily as unsaturated fats.

单选题Ford Abandons Electric Vehicles The Ford motor company"s abandonment of electric cars effectively signals the end of the road for the technology, analysts say. General Motors and Honda ceased production of battery-powered cars in 1999, to focus on fuel cell and hybrid electric gasoline engines, which are more attractive to the consumers. Ford has now announced it will do the same. Three years ago, the company introduced the Think City two-seater car and a golf cart called the THINK, or Think Neighbor. It hoped to sell 5,000 cars each year and 10,000 carts. But a lack of demand means only about 1,000 of the cars have been produced, and less than 1,700 carts have been sold so far in 2002. "The bottom line is we don"t believe that this is the future of environment transport for the mass market," Tim Holmes of Ford Europe said on Friday. "We feel we have given electric our best shot." The Think City has a range of only about 53 miles and up to a six-hour battery recharge time. General Motors" EVI electric vehicle also had a limited range of about 100 miles. The very expensive batteries also mean electric cars cost much more than petrol- powered alternatives. An electric Toyota RAV4 EV vehicle costs over $42,000 in the US, compared with just $17,000 for the petrol version. Toyota and Nissan are now the only major automanufacturers to produce electric vehicles. "There is a feeling that battery electric has been given its chance. Ford now has to move on with its hybrid program, and that is what we will be judging them on, "Roger Higman, a senior transport campaigner at UK Friends of the Earth, told the Environment News Service. Hybrid cars introduced by Toyota and Honda in the past few years have sold well. Hybrid engines offer greater mileage than petrol—only engines, and the batteries recharge themselves. Ford says it thinks such vehicles will help it meet planned new guidelines "on vehicle emissions" in the US. However, it is not yet clear exactly what those guidelines will permit. In June, General Motors and Daimler Chrysler won a court injunction, delaying by two years Californian legislation requiring car-makers to offer 100,000 zero-emission and other low-emission vehicles in the state by 2003. Car manufacturers hope the legislation will be rewritten to allow for more low-emission, rather than zero-emission, vehicles.

单选题From my standpoint , you know, this thing is just ridiculous.

单选题The life of London is made up of many different elements .

单选题University Physics University Physics is intended for students of science and engineering. Primary emphasis is on physical principles and problem-solving; historical background and specialized practical applications have been given a place of secondary importance. Many worked-out examples and an extensive collection of problems are included with each chapter. In this new edition, the basic philosophy and outline and the balance between depth of treatment and breadth of subject-matter coverage are unchanged from previous editions. We have tried to preserve those features that users of previous editions have found desirable, while incorporating a number of changes that should enhance the book's usefulness. The textbook is adaptable to a wide variety of course outlines. The entire textbook can be used for an intensive course two or three semesters in length. For a less intensive course, many instructors will want to omit certain chapters or sections to tailor the book to their individual needs. The arrangement of this edition facilitates this kind of flexibility. Conversely, however, many topics that were regarded a few years ago as of peripheral (外围的、次要的) importance and were omitted from introductory courses have now come to the fore again in the life sciences, earth and space sciences, and environmental problems. An instructor who wishes to stress these kinds of applications will find this textbook a useful source for discussion of the appropriate principles. In any case, it should be emphasized that instructors should not feel constrained (受约束的) to work straight through the book from cover to cover. Many chapters are, of course, inherently sequential in nature, but within this general limitation instructors should be encouraged to select among the contents those chapters that fit their needs, omitting material that is not relevant to the objectives of a particular course.

单选题The child couldn't comprehend the profound text book.A. interpretB. readC. understandD. translate

单选题Pop Music in Africa Young musicians in African countries are creating a new kind of pop music. The tunes and the rhythms of their music combine African traditions with various forms of music popular today, such as hip-hop, rap, rock, jazz, or reggae. The result is music that may sound familiar to listeners anywhere in the world, but at the same time is distinctly African. It is different also in another way. Many of the songs are very serious and they deal with important social or political issues in Africa today. Eric Wainaina is one of these African musicians. He grew up in Nairobi, Kenya, in a family of musicians. As a teenager, he listened to pop music from the United States, and later he moved to Boston to study at the Berklee College of Music. Now he has produced a CD. in Kenya. Eric's most popular song, "Land of 'A. Little Something'" is about Kenya's problem of bribery, or paying others for illegal favors. He wants people to listen to his songs and think about how to make Kenya a better place to live. Another musician who writes serious songs is Witness Mwaijaga from Tanzania. Her own experiences have helped her understand the suffering of many African women. At the age of fifteen she lost her home, but she was luckier than other homeless young people. She could make a living by writing songs and singing on the street. By the time she was eighteen years old, she had become a star. Her songs are written in rap or hip-hop style about the problems that she sees in Tanzania, especially AIDS and the lack of rights for women. Baaba Maal, from Senegal, also feels that pop music must go beyond entertainment. He says that in Senegal, storytellers have always been important people. In the past, they were the ones who kept the history of their people alive. Baaba believes that songwriters now have a similar responsibility. They must write about the world around them and help people understand how it could be better. The words of his songs are important, in fact. They speak of peace and cooperation among Africans, as well as the rights of women, love for one's family, and saving the environment. One of South Africa's most popular musicians is Brenda Fassie. She is sometimes compared to Madonna, the American pop star, because she likes to shock people in her shows. But she also likes to make people think. She became famous in the 1980s for her simple pop songs against apartheid. Now that apartheid has ended, her songs are about other issues in South African culture and life. To sing about these, she uses local African languages and a new pop style called kwaito. In recent years, people outside of Africa have also begun to listen to these young musicians. Through music, the younger generation of Africans are connecting with the rest of the world and, at the same time, influencing the rest of the world.

单选题Gambling is lawful in Nevada.

单选题 Volcanoes There are thousands of volcanoes (火山) all over the world. What makes volcanoes? What happens? The inside of the earth is very hot. Because it is very, very hot, the rock has melted like ice. It has become liquid, like water. It is always boiling, like water in a kettle. If you have seen a kettle boiling, you know that the steam and boiling water try to get out. The very hot melted rock inside the earth also tries to get out. Usually it cannot because the outside of the earth is too thick and strong. But in some places the outside of the earth is thin and weak. Sometimes a crack appears. The hot melted rock, which we call "lava" (熔岩), pushes out through the crack and bursts through. Steam and gas shoot up into the air and the hot melted lava pours out. Big pieces of rock may be thrown high into the air. After a while the volcano becomes quiet again. The melted lava becomes hard. Later the same thing happens again and again. Each time more hot lava pours out on top of the cold lava and then becomes hard. In this way a kind of mountain is built up, with a hole down the middle. Perhaps the volcano will then be quiet. Perhaps it will start again hundreds of years later. Vesuvius is the name of a very famous volcano in Italy. It first came to life many, many years ago. It was quiet for hundreds of years. Then in the year 79 it suddenly burst. A great cloud of smoke shot up into the sky with great burning rocks. Hot lava poured clown its sides. About 3,000 people were killed. This has happened again many times since that year. Sometimes no damage was caused, or only little damage. But there was serious damage in the years 472, 1631, 1794, 1861, 1872 and 1906. You can see that a volcano can stay alive for many years. There was also serious damage in 1914 hut there has not been any since that year.